Eternal vigilance is the price of ... um, well, guess we can't say that anymore. We might get sued.

Mostly when we think of threats to free speech, it's government actions or laws we have in mind -- the usual bizarre stuff like veggie libel laws or attempts to keep government actions or meetings secret from the public.

Sometimes you get a political case, like then-Gov. George W. Bush's effort to stop a Bush-parody site on the Internet. The parody, run by a 29-year-old computer programmer in Boston named Zack Exley, annoyed Bush so much that he called Exley "a garbageman" and said, "There ought to be limits to freedom." (That's not a parody -- he actually said that.)

Bush's lawyers warned Exley that he faced a lawsuit. Then they filed a complaint with the Federal Elections Commission demanding that Exley be forced to register his parody site with the FEC and have it regulated as a political committee.

This fits in with the four instances in which faculty members at the Bush School of Government and Public Service in our fair state were reprimanded at the behest of Bush associates for saying less-than-glowing things about our then-governor.

But this is petty stuff compared to corporate efforts to curb free speech.

SLAPP suits (for "strategic lawsuits against public participation") are a serious menace to free speech. The latest example is a real prize: The Consumers Union, publisher of Consumer Reports, has already spent $10 million defending itself against a lawsuit filed by Isuzu Motors Ltd. because, eight years earlier, Consumer Reports rated the Isuzu Trooper "not acceptable" for safety reasons. And the case has not yet reached trial.

And that is the real menace of SLAPP suits. It's not that corporations win them, but that they cost critics so much money that the critics are silenced -- and so is everyone else who even thinks about raising some question about a corporate product or practice.

Isuzu claims that CU's reports are "not scientific or credible," but the company's internal memos state that the "lawsuit is a PR tool" and "when attacked, CU will probably shut up." According to a study by two University of Denver law professors, "Americans by the thousands are being sued, simply for exercising the right to speak out on public issues, such as health and safety."

New York Supreme Court Judge J. Nicholas Cobella told PR Watch in Madison, Wis.: "The longer the litigation can be stretched out ... the closer the SLAPP filer moves to success. Those who lack the financial resources and emotional stamina to play out the 'game' face the difficult choice of defaulting despite meritorious defenses or being brought to their knees to settle. ... Short of a gun to the head, a greater threat to First Amendment expression can scarcely be imagined."

PR Watch also quoted George Pring and Penelope Canan, authors of the 1996 book "SLAPPs: Getting Sued for Speaking Out."

"Initially, we saw such suits as attacks on traditional 'free speech' and regarded them as just 'intimidation lawsuits,'" the two authors say. "As we studied them further, an even more significant linkage emerged: The defendants had been speaking out in government hearings, to government officials or about government actions. ... This was not just free speech under attack. It was that other and older and even more central part of our Constitution: the right to petition government for redress of grievances, the 'Petition Clause' of the First Amendment."

Some examples of SLAPP suits from PR Watch:

* In Las Vegas, a local doctor was sued for his allegation that a city hospital violated the state's cost-containment law.
* In Baltimore, members of a community group faced a $252 million lawsuit after circulating a letter questioning the property-buying practices of a local housing developer.
* In West Virginia, an environmental activist was sued for $200,000 for criticizing a coal-mining company for activities that were poisoning a local river.
* In Pennsylvania, a farmer was sued after testifying to his township supervisors that a low-flying helicopter owned by a local landfill operator caused a stampede that killed several of his cows.
* In Washington state, a homeowner found that she couldn't get a mortgage because her real-estate company had failed to pay taxes owed on her house. She uncovered hundreds of similar cases, and the company was forced to pay hundreds of thousands of dollars in back taxes. In retaliation, it sued the woman for slander and dragged her through six years of legal harassment before a jury found her innocent.
* In Missouri, a high-school English teacher was sued for $1 million after complaining to a weekly newspaper that an incinerator burning hospital waste was a health hazard.

Unlike the average citizen, Consumers Union has the resources to defend itself against the Isuzu suit. It's a nonprofit organization, and Consumer Reports accepts no advertising, lest there be any appearance of bias, and never grants permission for any commercial use of its name or test results.

It accepts no contributions from corporations or law firms or even individuals if the check bears a business imprint. The 60-year-old magazine is supported by the generations of smart consumers who always consult Consumer Reports before making any major purchases.

As we have seen with tort deform, it is not difficult to close off access to the courts for certain kinds of lawsuits. I can't think of a more meritorious and constitutional cause.